EV Liquid Cooling Layout for Parallel Power Electronics Heat Control

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Solution Overview

Problem

Conventional liquid cooling and air cooling systems are inadequate for effectively cooling the various components of electric vehicles, beyond just engine components.

Innovation Solution

A liquid cooling system for electric vehicles that includes a radiator, multiple coolant pumps, an inverter, an electric motor, a heat exchanger, an Onboard Battery Charger with a DC-to-DC converter, and a secondary DC-to-DC converter, all connected in parallel coolant path circuits to efficiently circulate coolant and manage heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional liquid cooling systems are used for engine components only, then engine cooling is adequate, but cooling for additional electric vehicle components (inverter, electric motor, battery charger, DC-to-DC converter) is insufficient

Engineering Contradiction:
Improvecooling coverageVSAvoidcomponent temperature management
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The liquid cooling system is designed to serve multiple functions by cooling various components including the engine, inverter, electric motor, battery charger, and DC-to-DC converter through a unified coolant circulation system with multiple pumps and radiators, thereby achieving universal cooling coverage across all heat-generating components

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cooling system is segmented into multiple independent coolant circulation circuits, each with its own coolant pump and radiator configuration, allowing targeted cooling of specific components (engine circuit, inverter circuit, motor circuit, battery charger circuit, DC-to-DC converter circuit) while maintaining overall system coordination

Inventive Principle:
Principle #1Segmentation

2Productivity

If multiple coolant pumps and parallel coolant path circuits are implemented, then cooling efficiency for multiple components is improved, but system complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcooling system structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cooling system divides components into separate circulation circuits based on their cooling requirements, with each circuit having its own coolant pump and radiator configuration. This segmentation allows independent optimization of cooling flow for each component while maintaining manageable system complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple coolant pumps are implemented to serve different circuits simultaneously, with each pump dedicated to specific components. This multi-functional approach enables efficient cooling of multiple heat-generating components in parallel, improving overall cooling productivity while distributing system complexity across independent subsystems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides efficient cooling for critical components of electric vehicles, enhancing their performance and reliability by effectively managing heat generation.

Implementation Method 1

a radiator to cool a coolant when the coolant flows through the radiator

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 2

an inverter to be cooled by the coolant, an electric motor to be cooled by the coolant

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a heat exchanger through which the coolant and another liquid can circulate

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4541619A1Liquid cooling system for an electric vehicle
Publication Date: 2025.04.23 KUBOTA CORP
  • EP4541619A1 patent drawingFigure 1
  • EP4541619A1 patent drawingFigure 2
  • EP4541619A1 patent drawingFigure 3

AI summary

A liquid cooling system (1) includes a radiator (532) to cool a coolant when the coolant flows through the radiator (532), a first coolant pump (356L) to circulate the coolant, a second coolant pump (356R) to circulate the coolant, an inverter (6) to be cooled by the coolant, an electric motor (45) to be cooled by the coolant and connected to the inverter (6), a heat exchanger (381) through which the coolant and another liquid can circulate, an Onboard Battery Charger with a DC-to-DC converter (7) to be cooled by the coolant, and a secondary DC-to-DC converter (382) to be cooled by the coolant. The first coolant pump (356L) and the second coolant pump (356R) are each connected to the radiator (532).